Four test guidelines (TGs) have recently been finalised and adopted by the OECD.

TG 433 has been adopted to assess acute inhalation toxicity by the fixed concentration procedure (FCP). This new method allows GHS classification whilst generally using fewer experimental animals, since lethality is not the principle endpoint being assessed.

The guidelines for the 28-day and 90-day inhalation toxicity studies (TGs 412 and 413, respectively) have been revised to enable the characterisation and testing of nanomaterials.

TG 442E for testing the activation of dendritic cells, as part of the Adverse Outcome Pathway (AOP) for skin sensitisation, has now been updated to incorporate the Interleukin-8 reporter gene assay (IL-8 Luc assay) and the U937 cell line activation test (U-SENS).

In addition, the following guidelines or updated guidelines have been proposed: